There has been known a pedal operation amount detection apparatus that includes (a) a transmitting member that transmits a pedal operation force, (b) a movement lever disposed so as to be movable with respect to the transmitting member, (c) a sensor rod disposed so as to be connected to the transmitting member and the movement lever, and (d) a deformable body that is disposed on the transmitting member and is deformed when the pedal operation force or a reaction force corresponding to the pedal operation force is transmitted from the movement lever to the deformable body, and that (e) electrically detects a pedal operation amount based on deformation of the deformable body. An apparatus described in Patent Document 1 is an example. When a pedal is operated, the movement lever is caused to contact the sensor rod, the sensor rod is moved in an axial direction in a manner such that an elastic member disposed between the sensor rod and the deformable body is elastically deformed, and the deformable body is deformed. Further, Patent Document 2 describes a technology in which a spring is disposed between a movement lever and an operating pedal (a transmitting member) and the movement lever is caused to contact a contact portion of a detector.